It is totally OK to re-use part of your already published book without citation. However, if the journal/publisher demands a citation, then you should do it. Because otherwise they will accuse you of copy right violation. I know it is nonsense, but the publishers/journal love to have citations, as it is good for their citation index.

I agree with the previous comments and it should be not necessary to cite our own work, especially when we are trying to contribute with novel evidence. I think another big reason why some researchers are cited themselves is not because they are blowing their trumpet to loud but is because in their institutes they are being evaluated in terms of number of citations per year.

Hector

As long as it is genuinely required for the manuscript under construction, it does not matter whether you cite your own article or other researcher's article. Idea is to disseminate our findings to the scientific world so that the society as a whole gets benefit.

Much of the self-plagiarism, as has been described here, is because of the pressure of citations that measure the worth of the work in the career metrics. If that is eased probably we would find significantly lesser amount of self-plagiarism as has been described here.

@Sai: I am not clear on how self-plagiarism can push up the number of citations you get. Surely, honestly admitting to writing some paragraph before by properly referencing it will increase the number of citable paragraphs?

Usually the journal owns the copyright, so the material is not yours for you to do anything you wish. So, when you quote it or paraphrase it or uses ideas from it you have to reference it, just as if it were someone else's work. The only difference is that you do not have to hunt down the text, because you know it and where it is! It is not trumpetblowing; it is good old fashioned honesty to include the reference to yourself as being the earlier source, and being the first person to have claimed that idea.

I personally believe that if they are taken thoughts and concepts relevant to previous works and publications, in the broadest sense, the citation is not strictly necessary.

Unlike, when they are taken paragraphs or entire sections of previous studies then the lack of citation can induce to consider this as auto-plagiarism.

I think it's also an act due to, both in terms of transparency both in terms of the history of ideas, even if it's the result of your personal genius and creativity.

@Ian, I have often seen research papers where the author has cited his own previous work along with much recent authorship in the same domain by other researchers. A,s a researcher when I am able to access a recent research of equal or extended value, why would I want to access a previous research except for choronological statement. If you have accessed some of the recent discussions on RG on author citation cartels, you would see various facets of the problem, where sometimes the publication houses have insisted on a few journal citations. I wish it was always an honest quote of a paragraph from a previous research published by the author. Best, Sai

On the occasion of a refereed, I recently had to assess an article that proposed original concepts and ideas, materials and quotes, dating back to an earlier work by the same author, written ten years earlier.

The work was published on the web but not on a Journal.

I requested to cite the original source.

In this case remains, however, the lack of advancement of scientific reflection and of research itself.

Self-plagiarism in my view is only a problem if one is trying to duplicate what he/she had already done as a new thing. If the individual is building upon what he/she had done previously and he/sh thinks that the data or arguments made in previous write ups would serve as either as a foundation or a buffer to the current arguments, then personally I see no problem with it.

As for influencing citation indexes, I don't think that self-plagiarism matters that much because in my understanding, what counts are unique citations not related to you but from others. That denotes the impact of your contribution to your field of endeavor.

self-plagiarism is a paradox anyhow. Indeed, normally the publishers owns the copyright but you still have the moral right to use your own work and reproduce it if needed. Because we normally tend to extend our previously conducted research rather than actually starting a new research topic every time we write, it is rather normal to find what you call "self-plagiarism". However we all try to avoid it as much as possible.

I think the issue is quite clear. You want to establish that you already have presented seem thoughts on the subject and also to establish that you have expertise in the field you are writing on. I believe that citing yourself is like establishing some train of thought/think that you already wrote one and are now continue to provide more in depth information to prove or disprove your previous findings. It gives the reader a chance to know your previous work and follow your chain of thoughts. Its not blowing your own trumpet but giving the chance to the reader to follow the sequence of ideas that you want to explore. The reader, if s/he doesnt understand your thoughts on the current issue can always look at your previous work to get an idea of what you are exploring. It also gives the chance for other writers to know and identify your work in their writings.

as a blind reviewer I found myself under the circumstances of having to reject an article. The author(s) were given the opportunity to submit something else. What I found myself reading was the same article, with a couple of different paragraphs under a different title. Nevertheless, apart from special cases like this one, I wouldn't have anything to say about citing or quoting past research. Even something that has already been published but provides new data is fine for me.

The way I see this question, I can attempt to answer it by asking another question, which for me, is only an extention of the former, thus: Why is it wrong for a researcher to resubmit an earlier published article to another journal with a different title, after all, it is her/his work? I believe that if you could quote your self extensively in a new work without reference, there would be nothing wrong in resubmitting a previously published article to another journal with a different title. My 2 pence. Please note that I am not presently at the University of Toronto.

@Barnabus: It is wrong because the reader is fully entitled to believe that the second article is original. Also, both journals will claim copyright. Last, it is fraud because the author signs a declaration that the article is an original, unpublished work.

@Barnabas. It is only possible when both journals agree.

another thing is revision. Authors usually revise and edit their books and publish a new edition. In my humble opinion it should be possible to do it with papers too. In that case one may sue his/her own previous text but should clearly say that it is based on that previous paper and should make it clear what is the value of this revision.

@ Nicla. Don't you think that authors have the right to disagree with you?

I think one needs to be very careful here. Firstly, as others have commented, when submitting an article to a journal you sign a form stating that the content has not been published elsewhere. Secondly, if, presumably you have written two articles that contain different titles (even if, for the sake of argument the focus is similar) then why would you see it as legitimate to write the same content? Surely the focus will be different. Of course, there may be arguments that you want to reuse in the second article. This is legitimate. But here you can make reference to your previous article and describe it using different words.

@Gray. Look at an instance where you carried out a study and brought out two papers from the research with different objectives and aim but probably related data. And this papers are published the same time. How would you reference this or would you as a publisher accuse plagiarism?

@Clement. Firstly you could only reference the first paper in the second paper if the first paper had been published, or accepted for publication and hence 'in print'. You can't reference yourself in something that has not been published. But once the first paper is published you can legitimately reference yourself in the same way that you would reference anyone else.

Referencing yourself is no different to referencing someone else, except that you are probably more familiar with your own writings.

As I read it, the only purpose of self-plagiarism would be to artificially try to inflate your number of publications. But why do this when the simple Google search by the referee will always reveal your deceit?

I agree with Ian here. Generally, it is OK to self-reference and the oft-cited issue of 'salami-slicing' is often a mute one. Unless an author is intentionally trying to deceive both publisher and reader by passing off largely 'replicated' works as original - then no harm is done. I publish quite a lot in my specialist field and I often cite my (and other colleagues)work. As Ian suggests, I know my work well and it has an on-going 'theme' to it. Other authors often multiple cite my work - so why wouldn't I?

Dear all,

Thank you for your valuable views. In my point of view, you have to show the reference of borrowed ideas, even yours ( in previous work). Remember the role of references is to show how much you view previous connected ideas/ theories and concepts to the original one. Again providing the reference of your own works gives the reader the extent to which you value your previous works and the ways you try to connect your previous ideas to the new ones ( by adding point, contrasting, amending, etc), which can be considered as part of professional development in your research.

In brief, it is necessary and advisable to show reference of one's previous works once used in the current work; if not this is self plagiarism.

There are also rules for this. For example, many publishers give the permission beforehand that you may use part of this publication for papers or book chapters. But they ask for giving the correct citation.

Huh!!!! This is serious. Some authors have one classical way of introducing all their papers. You could just cover the author details and identify the writer from the introduction. ......

What makes me raging in this issue, is that some journals do not let use your own words even if these are put in "" and cited. how can you rewrite methodics, if it is used in several research topics? One time, OK, it is rewording. Second time you sacrifice something from it. Then it becames language issue - especially for non-native speakers.

If it is put in quotes and cited it is not plagiarism! It is research business as usual!

Plagiarism = to use another person's idea or a part of their work and pretend that it is your own (Cambridge Dictionaries Online).

It is hard to understand how adding "self" in front of plagiarism can make any sense. Does it mean: "to use your own ideas and pretend they are your own"?

So, I don't like the term much but I recognise the concept it has come to represent as unprofessional and unnecessary. Unprofessional because it is like a student trying to submit the same piece of work for two courses. Unnecessary because most research projects have multiple angles that can be mined for new papers, and also because where there is a need to repeat some segments they can be cross-referenced.

@ Dear All,

Here is a relevant question with this topic.

https://www.researchgate.net/post/Is_plagiarism_correlated_with_lack_of_intelligence_or_lack_of_responsibility?cp=re65_x_p3&ch=reg&loginT=6mbecFPumdBuiZEHa6Qx9DpPAANAPKqQ5qhprF0IVdRDxHbhIAVfOw**&pli=1#view=5317a226d039b11c0b8b45c0

https://www.researchgate.net/post/Is_plagiarism_correlated_with_lack_of_intelligence_or_lack_of_responsibility?cp=re65_x_p3&ch=reg&loginT=6mbecFPumdBuiZEHa6Qx9DpPAANAPKqQ5qhprF0IVdRDxHbhIAVfOw**&pli=1#view=5317a226d039b11c0b8b45c0

Not sure that I view it as unprofessional David - and certainly not as unnecessary - for two reasons. I used to cite my early work routinely in my early publishing career to increase my reputation and visibility. Why would any neophyte researcher not want to do that. As long as the citation is not 'forced' into the article - that is fine. Nowadays - i'm an established 'name' in my field - and not too many people publish in that field. Therefore, when i write - I'm bound to cite some of my work. Your suggestion that 'all research should be new by researchers' is a rare one; most follow specific paths. I agree with your 'multiple angles' interpretation - but that usually means 'related' to each other; therefore the citations will often be repeated.

Dean, we might be writing at cross purposes here. I was writing about self-plagiarism (topic of the question), you seem to be talking about self-citation.

I was not disagreeing with citing oneself and I want to be clear that I do not see that as self-plagiarism. For the reasons given by many contributors here I think self-citation (referring to one's own previous work) is fine. Surely self-plagiarism is re-using without making clear that it is reused. I stand by my description of that as unprofessional. On your other point, I definitely did not say that all research should be new, I said that usually the multiple angles of the research could be used to produce new papers. I don't think paper=research, the paper reports something from the research. I agree entirely that papers are likely to be related and this may lead to repeating certain pieces of information, findings or views. I was simply saying that where repetition occurs the author should make it clear through cross-referencing (cross-referencing between papers = self-citation, not self-plagiarism).

Good response David - and I would fully endorse your stance. It's part of the semantics around self-plagiarism - but definitely worth elaborating on and expanding on. The term 'salami-slicing' has been a contentious buzz-word/s that tends to incorporate both stances - self-plagiarism and self-citation. The distinction is often not made - so well done that you have here. We're on the same page I feel.

Thank you all for your beautiful contributions. But Dean just cropped in something which i would like us to discuss. And this is about the issue of "salami-slicing". On what premise would you say someone has done "salami-slicing"? I want to believe that lengthy paper/research can be presented in parts and even some journals/ publishers stipulate the number of pages they demand from you. In that instance, it will be impossible not to "salami-slice"- sorry for the use of the word that way.

Can someone define salami slicing? It is an intriguing term but one I have never heard before (outside of a delicatessen). Thanks.

David - not sure of the exact origination of salami-slicing - but I understand it to mean something like a 'stick of rock' from an English seaside town. That may confuse you further still. It's a stick of candy with the name of the seaside town embedded throughout it. Wherever you cut it, the name appears the same. So, salami-slicing in an academic sense is the presentation of personal research that is 'very similar' to something that you have presented previously.

I suppose that unlike a T-bone steak, every slice of a salami looks like any other.

Hit the nail-on-the-head Ian!! No matter which order or way you put it back together (if you haven't eaten it that is) - it will look roughly the same as the original.

I love the irony of this:

http://retractionwatch.com/2015/04/01/you-cant-make-this-stuff-up-plagiarism-guideline-paper-retracted-for-plagiarism/

Self-plagiarism is misleading and against integrity, any research should come up with new knowledge that advance our understanding. Without proper citation, self-plagiarism deceive the reader by implying that the paper presenting completely new discoveries or knowledge. In addition, you do not own those words if you use it in previous published research for the copyrights reasons.